Thesis (MScEng (Mathematical Sciences. Applied Mathematics))--University of Stellenbosch, 2006. / This work entails the improvement of an existing three dimensional pore-scale model.
Stagnant zones are included, the closure of the volume averaged pressure gradient is improved
and an improved calculation of pore-scale averages, using the RUC, is done for the
model to be a more realistic representative of the REV and thus of the foamlike material.
Both the Darcy and the Forchheimer regimes are modelled and a general momentum
transport equation is derived by means of an asymptotic matching technique. The RUC
model is also extended to cover non-Newtonian flow. Since metallic foams are generally
of porosities greater than 90%, emphasis is put on the accurate prediction of permeability
for these porosities. In order to improve permeability predictions for these high porosity
cases an adaptation to the RUC model was considered, whereby rectangular prisms were
replaced by cylinders. Although this adaptation appears to give more accurate permeabilities
at very high porosities, its implementation in a generalised model seems impractical.
The prediction of the characteristic RUC side length is discussed and results of both the
cylindrical strand model and the square strand model are compared to experimental work.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/2960 |
| Date | 03 1900 |
| Creators | Wilms, Josefine |
| Contributors | Du Plessis, J. P., University of Stellenbosch. Faculty of Science. Dept. of Mathematical Sciences. Applied Mathematics. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | University of Stellenbosch |
Page generated in 0.0019 seconds